As a disc-shaped recording medium, employed as a data recording medium, a so-called compact disc (CD), which is an optical disc 12 cm or 8 cm in diameter, and an optical disc, 64 mm in diameter, which renders data re-recording possible even though it is further reduced in size, are presented to the market. In keeping pace with the coming into use of these optical discs, an apparatus for reproducing data recorded on the CD and an apparatus for recording data on and for reproducing the recorded data from the optical disc with a diameter of 64 mm, are also presented to the market.
Meanwhile, since the recording and/or reproducing apparatus employing a re-recordable optical disc with a diameter of 64 mm has been developed and presented to the market, the number of users who re-record the music data or other information recorded on the CD on the optical disc with the diameter of 64 mm to listen to the music data or the other information by the recording and/or reproducing apparatus designed for use with the optical disc with the diameter of 64 mm.
In such case, the CD reproducing device is connected by a connection cord to the recording and/or reproducing device for an optical disc with a diameter of 64 cm, the operation of the respective devices is controlled by a controller, such as a remote controller, the CD reproducing device is playback-paused state, the recording and/or reproducing device is recording-paused state, the paused state of the two devices is released simultaneously to reproduce the music data or the like information, referred to below simply as data, from the CD reproducing device, and the data reproduced from the CD is sent to the recording and/or reproducing device for recording on the optical disc with a diameter of 64 mm.
Referring to FIGS. 1 to 3, a dubbing system for recording CD data on an optical disc with a diameter of 64 mm is explained.
FIG. 1 shows the structure of a dubbing system, whilst FIG. 2 is a block diagram showing the structure of a CD reproducing device, and FIG. 3 is a block diagram showing the structure of an recording and/or reproducing device for an optical disc with a diameter of 64 mm.
The dubbing system 10, shown in FIG. 1, includes a CD reproducing device 12, a recording and/or reproducing device 14 for an optical disc with a diameter of 64 mm, and a controlling device 16, connected to system controllers 28, 52 of the CD reproducing device 12 and the recording and/or reproducing device 14, respectively, to control the operation of the two devices. The dubbing system, shown in FIG. 1, sends data from a signal processor 24 of the CD reproducing device 12 to a compression/expansion encoder/decoder 42 of the recording and/or reproducing deice 14, as the operations of the CD reproducing device 12 and the recording and/or reproducing device 14 are controlled by the controlling device 16. The data reproduced by the CD reproducing device 12 is recorded on the optical disc with the diameter of 64 mm by the recording and/or reproducing device 14.
In the system of FIG. 1, it is shown schematically that data is sent from the signal processor 24 to the compression/expansion encoder/decoder 42. Specifically, it is sufficient if an output of the digital output terminal of the CD reproducing device 12 is sent through a digital input terminal of the recording and/or reproducing device 14 to the encoder/decoder 42.
The CD reproducing device 12, used in the dubbing system 10 shown in FIG. 1, is a commercially available CD reproducing device for rotationally driving a CD at a CLV by a spindle motor 17 ro read out data recorded on the CD by an optical pickup 18 to route the output signal from the optical pickup 18 through an RF amplifier 20 to a demodulating unit 22. The demodulating unit 22 demodulates an EFM (eight-to-fourteen modulation) of an output signal from the RF amplifier 20 to route the demodulated output signal to the signal processor 24. The signal processor 24 routes the output signal of the demodulating unit 22 to an error correction unit 32 to execute error detection and correction, and routes the output signal, corrected for detected errors, to a D/A converter 26. The D/A converter 26 converts the output signal from the signal processor 24 into analog audio signals which are outputted at an output terminal 26. The signal processor 24 routes sub-code data etc to a system controller 28. The RF amplifier 20 generates a variety of error signals, such as focussing error signals or tracking error signals, based on the output signal of the optical pickup 18, to route the error signals produced to a servo circuit 30. Based on the focussing error signals and the tracking error signals, among the error signals routed from the RF amplifier 20, the servo circuit 30 generates the focussing servo signals and the tracking servo signals to route the servo signals generated to the optical pickup 18. The optical pickup 18 displaces the objective lens, not shown, based on the focussing error signals and the tracking error signals, supplied thereto, to execute focussing servo and tracking servo operations. The spindle motor 17 is fed from the servo circuit 30 with spindle servo signals to cause rotation of the CD at the CLV.
On the other hand, the recording and/or reproducing device 14 for an optical disc with a diameter of 64 mm, shown in FIG. 3, employs a magneto-optical disc as a recordable optical disc. This recording and/or reproducing device 14 is fed with analog audio signals from a microphone or an acoustic recording and/or reproducing device through an input terminal to an A/D converter 40. The A/D converter 40 converts the analog audio signals to digital audio signals, which are routed to the compression/expansion encoder/decoder 42. For recording on the optical disc D having a diameter of 64 mm, the compression/expansion encoder/decoder 42 compresses the digital audio signals routed from the A/D converter 40 in accordance with MDCT (Modified Discrete Cosine Transform).
Output data of the encoder/decoder 42 is transiently written in a memory 43a through a memory controller 43. For recording on the optical disc D, the memory controller 43 controls the write/readout of the memory 43a so that the readout speed of data written in the memory 43a will be faster than the write speed of output data in the memory 43a from the encoder/decoder 42. In reproducing the optical pickup D, the memory controller 43 controls the write/readout of the memory 43a so that the readout speed of data written in the memory 43a will be slower than the write speed of output data in the memory 43a from the encoder/decoder 42.
The output data from the encoder/decoder 42, transiently written in the memory 43a, is read out from the memory 43a at a transmission rate faster than the write speed of the output data in the memory 43a, and routed to a modulation/demodulation and error correction unit 44. During recording on the optical disc D, the modulation/demodulation and error correction unit 44 performs error correction and encoding on the output data read out from the memory 43a to perform EFM. The recording data, outputted by the modulation/demodulation and error correction unit 44, is sent to a head driving unit 46 and thence routed to a magnetic head 48 based on the driving signals from the head driving unit 46.
The magnetic head 48 is placed facing the optical pickup 58, with the optical disc D in-between, and is moved in the radial direction of the optical disc D by a feed mechanism, not shown, having a feed motor 56 as a driving source. The magnetic head 48 sends a perpendicular magnetic field, modulated on the basis of recording data by driving signals sent from the head driving unit 46, to the optical disc D. The data is recorded on the optical disc D by the laser light of an output level necessary for recording being illuminated on the optical disc D from the optical pickup 58, with the perpendicular magnetic field, modulated on the basis of the recording data, being supplied from the magnetic head 48 to the optical disc D.
In recording the data on the optical disc D, the optical pickup 58 illuminates the laser light of an output level necessary for recording, whereas, in reproducing data from the optical disc D, the optical pickup 58 illuminates the laser light of an output level lower than that in recording to read out the data recorded on the optical disc D by exploiting the Kerr effect. The optical pickup 58 includes a semiconductor laser element, as a light source for outputting the laser light, a photodetector having plural light receiving units for receiving the reflected light from the optical disc D, an objective lens for converging the laser light outputted by the semiconductor laser element on a recording surface of the optical disc D, an actuator for causing movement in the focussing and tracking directions, based on the focussing servo signals and the tracking servo signals from servo circuit 54 as later explained and an optical system for directing the laser light outputted by the semiconductor laser element to the objective lens or directing the reflected light from the optical disc D to the photodetector.
In reproducing the optical disc D, the data read out from the optical disc D, that is the output signal of the photodetector of the optical pickup 58, is amplified by an RF amplifier 59 and thence supplied to the modulation/demodulation and error correction unit 44 where the signal is processed with EFM demodulation and error correction. Output data of the modulation/demodulation and error correction unit 44 is written in the memory 43a through the memory controller 43. At this time, the output data of the modulation/demodulation and error correction unit 44 is read out from the memory 43a at a transmission rate slower than the output data writing speed in the memory 43a. When the output data is written to the full storage capacity of the memory 43a, data readout from the optical disc D by the optical pickup 58 is halted, with the optical pickup 58 being then paused and placed in a standby state at the readout interrupted position of the optical disc D. As a result, the data is read out intermittently from the optical disc D. On the other hand, even if there occurs the so-called track jump in which the scanning position by the optical pickup 58 is skipped under an impact applied from outside to the recording and/or reproducing apparatus 14 during the optical disc reproducing operation, the data stored in the memory 43a may be outputted. As the data stored in the memory 43a is read out, the scanning position of the optical pickup 43a is restored to the normal scanning position and data readout from the optical disc D is re-initiated to output analog audio signals in succession from the output terminal.
The data read out from the memory 43a is fed to the compression/expansion encoder/decoder 42 where it is processed with expansion. The digital audio signals, outputted by the encoder/decoder 42, is routed to a D/A converter 41 where it is converted to analog audio signals which are outputted at an output terminal.
The RF amplifier 59 generates various error signals, such as focussing error signals, tracking error signals and spindle error signals, based on the output signal from the optical pickup 58, to route the various error signals to the servo circuit 54. The servo circuit 54 generates focussing servo signals and the tracking servo signals, based on the focussing error signals and the tracking error signals supplied from the RF amplifier 59, to generate focussing servo signals and tracking servo signals, which then are supplied to the actuator of the optical pickup 58 to cause movement of the objective lens of the optical pickup 58 in the focussing and tracking directions. The servo circuit 54 also generates spindle servo signals, based on the spindle error signals sent from the RF amplifier 59.
The spindle servo signals, generated by the servo circuit 54, are routed to a spindle motor 50, which then rotationally drives the optical pickup with e.g., the CLV, based on the spindle servo signals supplied thereto.
The servo circuit 54 also generates signals driving the feed motor 56, based on low frequency components of the tracking error signals supplied from the RF amplifier 59, while generating feed signals required for accessing, based on a control signal supplied from a system controller 52, to route the generated feed signal to the feed motor 56. As a result, the optical pickup 58 and the magnetic head 48 are moved along the radius of the optical disc D.
The output signal of the RF amplifier 59 is routed to an address decoder 57 where address data of the optical disc D is extracted and routed to the modulation/demodulation and error correction unit 44 for error correction. The resulting data is routed to the system controller 52 so as to be used for e.g., the accessing operation.
The system controller 52 is made up of a micro-computer and controls the operation of the various components of the recording and/or reproducing device, such as the modulation/demodulation and error correction unit 44 or the memory controller 43.
In the dubbing system 10, described above, output signals of the signal processor 24 of the reproducing device 12, that is digital audio signals read out from the CD, are sent to the compression/expansion encoder/decoder 42 of the recording and/or reproducing device for compression and further modulation as well as error correction so as to be then recorded on the optical disc D. The control of the recording operation by the recording and/or reproducing device 14 of the digital audio signals outputted by the reproducing device 12 is by the system controller 28 of the reproducing device 12 and by the system controller 52 under control by the controlling device 16. Specifically, in the reproducing operation by the reproducing device 12 and the recording operation by the recording and/or reproducing device 14, the system controllers 28 and 52 are controlled in timed relation to each other by the controlling device 16.
If, in the above-described dubbing system, data is to be dubbed from the CD to the optical disc D having the diameter of 64 mm, both the CD reproducing device 12 and the recording and/or reproducing device 14 are operated so that the data recorded on the CD will be reproduced by the CD reproducing device 12 and so that the reproduced data will be recorded in real time on the optical disc D by the recording and/or reproducing device 14. The result is that the dubbing time is of the same duration as the reproducing time of the musical number recorded on the CD and which desirably is to be dubbed on the optical disc D.
The result is that the user has to wait near the CD reproducing device 12 and the recording and/or reproducing device 14, during the time the number recorded on the CD and which is desired to be dubbed is reproduced, owing to the operations of the CD reproducing device 12 and the recording and/or reproducing device 14. For example, if the CD reproducing time is 74 minutes and the totality of the musical numbers recorded on the CD is to be recorded on the optical disc D of the recording and/or reproducing device 14, the user has to wait for 74 minutes which is the time required in reproducing the totality of the musical numbers recorded on the CD.
In particular, if a certain musical number is selected from each of plural CDs for recording on the optical disc, the user has to wait until the recording operation on the optical disc is terminated in order to perform the CD exchanging operation. Since the standby time during which the user monitors the recording operation is long thus inconveniencing the user. So, a demand is raised for development of a system with a shorter standby time convenient for the user.
In the above explanation, dubbing on an optical disc, with a diameter of 64 mm, which permits recording from a CD, is taken as an example. However, a similar problem arises not only in the case of dubbing from the CD to the recordable optical disc but also in dubbing data from a first disc-shaped recording medium to the second disc-shaped recording medium if the recording speed for the second disc-shaped recording medium is slower than the reproducing speed from the first disc-shaped recording medium.